Mobile phones are widely used and become more intelligent.
People using the mobile phone stores a lot of programs and data in the mobile phone. When the mobile phone is not using certain programs or when the phone needs to be replaced, the programs and data in the mobile phone need to be removed. However, such deletion may not be thorough enough. Some unscrupulous people know how to retrieve data that may have been deleted by the user. This ability for unscrupulous people to retrieve delete data is a risk to data security.